Measuring the condition of a fluid used in a system is indicative of a variety of parameters that can affect the system. More so, measuring the condition of industrial fluids is highly important in industrial systems as it can lead to potentially high risk-involving circumstances. Industrial fluids like engine oil, hydraulic oil and lubricants are used in industrial systems ranging from automobile engines to large plants like petrochemical plants, power plants, metallurgical plants and to various other processes like mechanical processes, thermal-mechanical processes etc. Any unexpected failure or an accidental damage resulting from failure of or presence of impurities in such fluids can result in a hazardous situation. Technologies are required to constantly monitor these fluids. Several methods, including electrical, magnetic and optical are used to assess the condition of the fluid.
There are many electrical or magnetic devices available to monitor the condition of a fluid as described in prior art reference “Smart sensing of oil degradation and oil level measurement in gasoline engines”, by Amyioo Basu et al. SAE 2000. However, the information that can be deduced about the condition of the fluid using electrical and magnetic methods is limited. On the other hand, there are not many devices available to monitor the condition of the fluid through optical means. Such devices that are available are complex in design, bulky, difficult to operate, expensive and sensitive to vibrations that occur in industrial systems. Also, there is no option of monitoring the fluid condition continuously with respect to time. In most devices, measurements are made periodically by ejecting samples of fluids using complicated arrangements of pumps and valves.
In prior art reference U.S. Pat. No. 6,151,108, an apparatus to optically monitor the condition of the fluid using optical fibers is disclosed. The apparatus collects samples continuously using pumps and valves and guides an input optical signal through optical fibers and monitors the output. There is however, a time lag involved in monitoring the condition and hence exists the possibility of having skewed information about the condition of the fluid. The setup also involves a complex integration of pumps and valves making the apparatus bulky.
U.S. Pat. No. 5,644,239 discloses electrical and thermal methods to monitor the condition of the fluid, which are supported by optical methods. However, there is no emphasis on the use of optical methods or on making the measurements in real time.
Another prior art reference U.S. Pat. No. 6,825,921 discloses use of a multi optical property measurement system and claims use of at least two of absorption, luminescence, and scattering methods. However, the samples are observed only once as this is directed towards medical applications and the method is not operating under real time.
The present invention eliminates use of bulky devices for optical methods, the invention can easily be integrated in-line with the path of the fluid flow in the system it is being used. Placing the apparatus in-line with the fluid flow in the industrial system to capture the fluid sample and not hindering flow of the fluid sample enables the apparatus to make measurements continuously in real time. By collecting samples through an in-line integrated system, the problem of incorrect sampling, which might not be indicative of the actual condition of the bulk of the fluid, is also eliminated. The invention also makes use of measuring multiple optical methods simultaneously to monitor the condition of the fluid in order to determine accurately the condition of the fluid and to qualitatively predict the impurities present in the fluid.